Scielo RSShttp://www.scielo.cl/rss.php?pid=0717-345820080005&lang=es
vol. 11 num. 5 lang. eshttp://www.scielo.cl/img/en/fbpelogp.gifhttp://www.scielo.cl
Food biotechnology and education]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500001&lng=es&nrm=iso&tlng=es
It is clear that the future of our children will be marked by the development of two scientific disciplines: computing and biotechnology. Regarding the first, during recent years considerable progress have been done in many countries around the globe aimed at enhancing the teaching in these subjects and, at the same time, encouraging the use of computers in classrooms. On the contrary, training in biotechnology is absent in many secondary schools of the planet. This formative deficiency generates citizens whose opinion on the marketing of biotechnological products is easily manipulated by both defenders and opposers of biotechnology. This situation is of particular relevance when the item in question is food biotechnological applications that provoke an intense social debate and more specifically the so-called genetically modified foods (GM foods). In this article we report a survey carried out with 500 young Spanish consumers in order to discover their attitudes to GM foods. The work has been focused on the study of the perception of GM foods and their labelling. The results indicate that they are moderately receptive to GM foods but like to be informed through labelling. However, the most important conclusion of the survey is the lack of sufficient knowledge about food biotechnology and genetic engineering on the part of young Spaniards. It is therefore very important that an unbiased presentation of the scientific basis of biotechnology should be introduced in secondary education. In this sense, the project BIOEDUCAR is an important tool to introduce unbiased information about food biotechnology in the Latin America and Spanish secondary schools.Advances in the development of a noninvasive embryo model for the evaluation of the quality of cloned embryos subjected to different treatments]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500002&lng=es&nrm=iso&tlng=es
Total number of cells in cloned embryos is generally lower than that of in vivo derived embryos and in bovines cell allocation at the blastocyst stage, has been observed to be affected in a large proportion of cloned embryos. The current embryo staining procedures are toxic for mammalian cells and thus can not be used to determine the developmental potential of a stained embryo. Therefore, in the present study we sought to assess the feasibility to develop a noninvasive embryo model that would be suitable for the evaluation of cloned embryos subjected to different nuclear transfer and embryo culture procedures. For doing this, we stably transfected a bovine embryonic fibroblast cell line and generated a number of clones that constitutively expressed a red fluorescent protein (HcRed) in the nuclear compartment of the cell. Those clones with normal chromosomal content were further used as nuclear donor in nuclear transfer procedures (SCNT) to generate transgenic cloned embryos. These embryos expressed the red fluorescent protein in each blastomere, allowing their in vivo evaluation during development, thus demonstrating the potential of this model as a noninvasive tool for the assessment of the quality of cloned embryos.Assessment of genetic diversity in Venezuelan rice cultivars using simple sequence repeats markers]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500003&lng=es&nrm=iso&tlng=es
In Venezuela, pedigree analyses indicate that the rice varieties currently under cultivation are closely related. Effective breeding programs, based on knowledge of the genetic diversity of cultivars, are needed to broaden the genetic bases of rice germplasm in the country. In this study, we used a set of 48 simple-sequence-repeat (SSR) markers to assess the genetic diversity of 11 Venezuelan rice cultivars, released by the National Rice Breeding Program between 1978 and 2007. A total of 203 alleles were detected, the number of alleles (NA) per marker ranged from 2 to 9, with an average of 4.23. The average genic diversity (H) over all SSR loci for the 18 genotypes was 0.524, ranging from 0.105 to 0.815. Positive correlations were found between H at each locus, NA, the allele size range and the maximum number of repeats. Venezuelan cultivars showed lower H (mean = 0.37) and NA (total = 124, mean = 2.58) than the whole sample. UPGMA-cluster-analysis based on genetic distance coefficients clearly separated all the genotypes, and showed that the Venezuelan rice varieties are closely related. Molecular identification of 7 Venezuelan cultivars could be done with 9 primers pairs which produced 10 genotype-specific-alleles. Although the genetic diversity was low, SSRs proved to be an efficient tool in assessing the genetic diversity of rice genotypes. Implications of the low genetic diversity detected and relatedness of Venezuelan cultivars are discussed.Identification of a minimal microsatellite marker panel for the fingerprinting of peach and nectarine cultivars]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500004&lng=es&nrm=iso&tlng=es
The genetic characterization of 117 peach and nectarine cultivars (Prunus persica (L.) Batsch) using microsatellite (SSR) markers is presented. Analyzed genotypes include the complete list of cultivars under intellectual property (IP) protection in Chile. One hundred and two out of the 117 cultivars under study could be identified using only 7 SSRs. Other 5 cultivars were differentiated using 3 additional markers, but 5 pairs of genotypes were not differentiable. The average expected heterozygosity for the set of markers was 0.55, ranging from 0.28 in BPPCT-008 to 0.81 in CPPCT-022, with an F value of 0.37. A Neighbor-Joining dendrogram showed that, with few exceptions, peaches and nectarines clustered separately. These results are the basis for the development of a fingerprinting protocol for the unequivocal identification of most of the peach and nectarine cultivars officially registered in Chile.Novel s-triazine-degrading bacteria isolated from agricultural soils of central Chile for herbicide bioremediation]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500005&lng=es&nrm=iso&tlng=es
s-Triazine-degrading bacterial strains were isolated from long-term simazine-treated agricultural soils of central Chile. The number of culturable heterotrophic bacteria of these agricultural soils (7 x 10(6) CFU/g of dry soil) was not affected by simazine application on field. The simazine-degrading bacterial strains P51, P52 and C53 were isolated by enrichment in minimal medium using simazine as the sole nitrogen source. Resting cells of strains P51 and P52 degraded >80% of simazine within 48 hrs, whereas strain C53 was able to remove >60% of the herbicide. The atzA and atzD genes of the s-triazine upper and lower catabolic pathways were detected in strains P51 and C53, while only atzD gene was observed in strain P52. To compare the bacterial 16S rRNA gene sequence structure, ARDRA were performed using the restriction enzymes Msp1 and Hha1. ARDRA indicated that strain P52 was a different ribotype than C53 and P51 strains. For further characterization the novel isolates were identified by 16S rRNA gene sequencing. Strains C53 and P51 belong to the genus Stenotrophomonas and the strain P52 belongs to the genus Arthrobacter . s -Triazine-degrading bacterial strains isolated from contaminated soils could be used as biocatalysts for bioremediation of these herbicides.Obtainment of embryogenic cell suspensions from scalps of the banana CIEN-BTA-03 (Musa sp., AAAA) and regeneration of the plants]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500006&lng=es&nrm=iso&tlng=es
The purposes of this work were to obtain embryogenic cell suspensions (ECS) from scalps and to regenerate plants of the banana CIEN-BTA-03. Shoot apexes were grown in the scalp-induction medium of Murashige and Skoog plus BA and IAA, following four diverse treatments. The first two, ME22 and ME25, were solid media supplemented with (mg L-1) 22.7 BA plus 0.192 IAA, and 25 BA plus 0.217 IAA, respectively, all containing 1.8 g L-1 of phytagel, and subcultures were performed monthly and bimonthly over 16 months. The other two treatments, IT22 and IT25, resembled ME22 and ME25 but consisted in temporary immersion for four months without subcultures, followed by two months in solid media. The scalps were grown in callus-induction medium and embryogenic calluses were obtained with abundant somatic embryos, especially in scalps from IT25. About 10 to 15 embryos from each were transferred to 5 ml of multiplication medium to initiate the ECS. The scalps obtained from the IT25 treatment were the most successful as they led to ECS with high embryogenic capability. In addition, IT25 decreased the timespan required for the production of scalps. The obtained ECS gave rise to secondary somatic embryos. It showed a high multiplication index, as well as numerous mature somatic embryos, and good conversion of embryos and plant regeneration.Phytoplasma and virus detection in commercial plantings of Vitis vinifera cv. Merlot exhibiting premature berry dehydration]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500007&lng=es&nrm=iso&tlng=es
A new and devastating physiological disorder of Vitis vinifera cv. Merlot was recently reported, known as premature berry dehydration (PBD), which is characterized by plant growth reduction, induction of general senescence and pedicel necrosis in the fruit, causing significant reductions in vineyard production. The causes of this disease remain unclear and previous reports suggest that it may be associated with phloem disruption and water provision. For this reason, any factor causing phloem disturbances could cause an important change in the berry water status. As some micro-organisms have been reported to disrupt phloem flow, we analyzed the occurrence of phytoplasma and viruses in commercial vineyards presenting PBD. In this study, a phytoplasma was detected by electron microscopy and nested PCR while virus infections were diagnosed by RT-PCR in samples collected during two growing seasons. The presence of phytoplasma only in samples from grape plants with PBD suggests that this pathogen may be one of the causal agents of this disorder. We suggest that the influence of other factors, such as virus infections, agronomic handling and environmental conditions also modulate berry dehydration. This is the first study at the microscopic and molecular levels that correlates phytoplasma presence with PBD.Introduction of antifungal genes in sunflower via Agrobacterium]]>http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000500008&lng=es&nrm=iso&tlng=es
There is evidence that overexpression of transgenes codifying antifungal proteins may confer protection to pathogen attack, and that this protection is increased due to the synergic effect of the expression of two or more genes. On the other hand it is well known that sunflower is a recalcitrant specie, highly difficult to be genetically transformed. In this context, the final aim of this project was to obtain sunflower plants expressing at least two antifungal genes, avoiding sequential transformation. The antifungal genes used encode for two enzymes that degrade the fungal wall (glucanase and chitinase), an osmotin and a ribosome inhibitor protein. Two types of transformation vectors were used: a more traditional system with a double cassette and a novel system producing a unique polyprotein with antifungal proteins released in equimolecular quantities. The polyprotein vector system generated hyperhydric shoots with necrotic areas and abnormal growth at the end of the tissue culture procedure, making impossible the use of this interesting vector in sunflower. Transformation assays carried out with the pHGC39 vector (including glucanase and chitinase genes) vector produced 0.83% efficiency, corresponding to 13 rooted shoots in kanamycin (Km) from a total of 1568 agroinfected shoots. T0 rooted shoots resulted positive by PCR analysis and were transferred to greenhouse to obtain their offspring. In addition, we corroborate the transformation protocol using Km as selective marker, previously described (Radonic et al. 2006) with a reporter gene, but in this opportunity with antifungal genes.